Theo Hobson at The Guardian:
Atheism derives from religion? Surely it just says that no gods exist, that rationalism, or 'scientific naturalism', is to be preferred to any form of supernaturalism. Actually, no: in reality what we call atheism is a form of secular humanism; it presupposes a moral vision, of progressive humanitarianism, of trust that universal moral values will triumph. (Of course there is also the atheism of Nietzsche, which rejects humanism, but this is not what is normally meant by 'atheism').
So what we know as atheism should really be understood as an offshoot of deism. For it sees rationalism as a benign force that can liberate our natural goodness. It has a vision of rationalism saving us, uniting us. For example, AC Grayling, in his recent book The God Argument: The Case Against Religion and for Humanism, argues that, with the withering of religion, 'an ethical outlook which can serve everyone everywhere, and can bring the world together into a single moral community, will at last be possible'. This is really Rousseau's idea, that if we all listened to our hearts, there would be 'one religion on earth'.
On one hand atheism is more coherent than deism – it neatly eliminates the supernatural. But on the other hand it has less self-knowledge: it does not understand that it remains fuelled by a religious-based vision of human flourishing.